Non-steroidal anti-inflammatory agents represent a well known class of pharmaceutical agents commonly referred to as NSAIDs. Such agents exhibit anti-inflammatory, analgesic and anti-pyretic activity and typically have other biological effects in humans, such as platelet aggregation inhibition activity. The NSAIDs also characteristically inhibit the synthesis of prostaglandins in well known in vitro assays. The NSAIDs provide more or less moderate non-narcotic analgesia and are typically used to alleviate mild to moderate pain, both chronic and acute, in a wide variety of situations. The NSAIDs are also characterized, more or less, by certain undesired or side effects, e.g. ulcerogenic effects, which are usually mainly of concern when administered at high doses and/or over long time periods, but side effects are judged of far less concern than with the stronger, narcotic analgesics.
The compound 1-(p-chlorobenzhydryl)-4-[2-(2-hydroxyethoxy)ethyl]-diethylenediamine (referred to generically as hydroxyzine) and its salt derivatives are known to be effective tranquilizers (see U.S. Pat. No. 2,899,436).
The search for analgesic agents of all kinds which will optimize the therapeutic effect and minimize undesired effects has been a long continuing quest in the attempt to find improved treatments. This search has included co-administrations involving analgesics, one with another or with a drug of another type. Among the wide variety of combined administrations which have been considered are those involving a tranquilizer and an analgesic. Such combinations have been mainly of interest in situations where both stress and great pain are anticipated or experienced, such as in surgical situations and the advanced stages of diseases such as cancer. For example, the literature reveals a number of clinical evaluations of the combination of hydroxyzine and a narcotic analgesic, generally co-administered by the i.v. or intramuscular routes, but the results in terms of analgesia have been largely judged to be additive.